Dry-cured Bacon Research Articles

TMT-labeled quantitative proteomic reveals the mechanism of proteolysis and taste improvement of dry-cured bacon with Staphylococcus co-inoculation

To understand the mechanism of co-inoculation of Staphylococcus xylosus and Staphylococcus vitulinus (SX & SV) on structural protein degradation and taste enhancement of dry-cured bacon, protease activities, protein degradation, surface morphology of proteins and taste parameters of dry-cured bacon with Staphylococcus inoculation were investigated. The dry-cured bacon with co-inoculation of Staphylococcus xylosus and Staphylococcus vitulinus showed the best taste attributes. High residual activities in cathepsin B + L (more than 1.6-fold) and alanyl aminopeptidase (more than 1.4-fold) accelerated structural protein degradation in SX & SV. 32 down-regulated proteins were identified in SX & SV by TMT-labeled quantitative proteomic compared with control group; myosin and actin showed the most intense response to the accumulation of sweet and umami amino acids, and atomic force microscopy confirmed structural proteins breakdown by morphological changes. The accumulation of glutamic acid, alanine and lysine was mainly responsible for taste improvement of dry-cured bacon with Staphylococcus co-inoculation.

The combination of high-throughput sequencing and LC-MS/MS reveals the mechanism of Staphylococcus inoculation on bacterial community succession and taste development during the processing of dry-cured bacon.

To understand the mechanism of co-inoculation of Staphylococcus vitulinus and Staphylococcus xylosus (SX&SV) on taste quality of dry-cured bacon, physicochemical parameters, microbial community, metabolite compositions and taste attributes were investigated during the processing of dry-cured bacon with Staphylococcus inoculation; the potential correlation between core bacteria and metabolites was evaluated, and the metabolic pathway of key metabolites was further explored. The values of pH, water activity and adhesiveness were significantly lower in SX&SV, and more than 2.56-fold and 2.15-fold values in richness and overall acceptance were found in SX&SV bacon than in CK bacon. The overwhelming advantage of Staphylococcus was confirmed in SX&SV by HTS. Sixty-six metabolites were identified by LC-MS/MS, and oligopeptides, amino acid derivatives and organic acids were the key components. Pearson correlation demonstrated that the accumulation of oligopeptides, amino acid derivatives and organic acids were positively correlated with high abundance of Staphylococcus. The pathways of purine metabolism, glutathione metabolism and glutamate metabolism were mainly involved in developing the taste quality of SX&SV. The co-inoculation of Staphylococcus vitulinus and Staphylococcus xylosus enhanced the taste attributes of dry-cured bacon. This work provided the theoretical reference to regulate the taste quality of fermented meat products by starter cultures of Staphylococcus during the manufacture. This article is protected by copyright. All rights reserved.

Effect of Seawater Curing Agent on the Flavor Profile of Dry-Cured Bacon Determined by Sensory Evaluation, Electronic Nose, and Fatty Composition Analysis.

The purpose of this study was to check the applicability of seawater as a natural curing agent by analyzing the difference it causes in the flavor of dry-aged bacon. Pork belly was cured for seven days, and dried and aged for twenty-one days. The curing methods included the following: wet curing with salt in water, dry curing with sea salt, brine curing with brine solution, and bittern curing with bittern solution. The seawater-treated groups showed a lower volatile basic nitrogen value than the sea-salt-treated groups (p < 0.05); dry curing showed a higher thiobarbituric acid reactive substance value than other treatments (p < 0.05). Methyl- and butane- volatile compounds and polyunsaturated fatty acids such as g-linolenic and eicosapentaenoic were the highest in the bittern-cured group, lending it superior results compared to those of the control and other treatments in sensory flavor analyses (cheesy and milky). Therefore, bittern is considered to have significant potential as a food-curing agent.

QUALITY AND TECHNOLOGICAL SUITABILITY OF MEAT FROM POLISH NATIVE BREEDS FOR THE PRODUCTION OF TRADITIONAL PORK PRODUCTS

Background. Organic production is identified with high quality of raw materials, health-promoting properties, and earlier – with animal welfare and sustainable development of agricultural production. Hence, the use of raw materials obtained from animals of native breeds is popular, which is associated with cultural heritage and support for local farms, especially for cattle producers. The production of salami type sausage, dry-cured bacon, dry-cured or cooked gammon, roasted ham in buckwheat or roulade of piglet, traditionally manufactured from regional meat, is also important for local authorities in promoting the region. Hence, it is important to highlight the qualities of available animal raw materials originating from domestic breeds. Results and conclusions. The meat and fat of native pig breeds ‘Puławska’ (Pw), ‘Złotnicka White’ (ZW) and ‘Złotnicka Spotted’ (ZS) are characterized by a different technological quality and unique con sumption value. A chemical composition affects the functional characteristics ‒ the water, protein and fat content has an impact on the texture profile, organoleptic quality and safety. TheZS and Pw meat hasgrea ter fatness compared to the ZW meat, while the ZW meat has a higher palmitic and oleopalmitic acid content. The Pw and ZS meat differs in fatty acids proportions (DA, LA, SA, AA, CLA). The pH24 and water retention of the Pw, ZW and ZS meat indicate resistance to DFD and PSE defects. The meat of Polish native breeds is suitable for the production of traditional meat products (Pw, ZW, ZS), cooked hams and sirloins (ZW, ZS), as well as dried, smoked and non-smoked sausages (ZS). The aim of this study was to describe the selected properties of the meat of three Polish native breeds of pigs (PW, ZW, ZS) that determine its quality and technological suitability for the production of pork products using traditional methods.

Sensory profile and likeability of Croatian traditional dry meat products from different regions

The aim of this paper was to determine the sensory profiles and likeability of two types of traditional dry-cured meat products from four Croatian regions (Central and Northern, Eastern, Western and Southern Croatia). For this purpose, 24 samples of dry-cured ham and 26 samples of dry-cured bacon were evaluated by a trained panel of 9 judges using quantitative descriptive analysis. It was found that the sensory profiles of dry-cured ham and bacon differed significantly in 12 and 13 of the 22 sensory traits, respectively. Nearly all likeability traits of dry-cured ham differed significantly between regions, with the exception of the cross-section likeability which was the only trait that differed among dry-cured bacon samples between regions. The results of principal component analysis (PCA) showed that the attributes of odour and aroma were most important for characterizing and differentiating dry-cured meat products. PCA analysis revealed a strong separation of samples between the Western Croatia region, where aromatic and spicy herb aroma was most important, and the Southern Croatia region, where buttery aroma and smoky odour were most important. Samples from the Central and Northern Croatia region were well recognized within the Southern Croatia region, possibly due to the use of smoke, but with less buttery aroma. Samples from the Eastern Croatia region were poorly recognized, having much overlap with other regions. It can be concluded that the influence of regions on sensory traits is evident regardless of the product, but the contribution of the region should be well defined and robust.

The Content of Polycyclic Aromatic Hydrocarbons in Slavonska slanina—Traditionally Smoked and Dry-Cured Bacon

The goal of this study was to determine the concentrations of 16 PAHs (PAH16) naphthalene—Nap, acenaphthylene—Anl, acenaphthene—Ane, fluorene—Flu, phenanthrene—Phen, anthracene—Ant, fluoranthene—Flt, pyrene—Pyr, benz[a]anthracene—BaA, chrysene—Chry, benzo[b]fluoranthene—BbF, benzo[k]fluoranthene—BkF, benzo[a]pyrene—BaP, indeno[1,2,3-cd]pyrene—InP, dibenz[a,h]anthracene—DahA and benzo[g,h,i]perylene—BghiP) in Slavonska slanina traditionally smoked bacon over open fire and industrially smoked on a smoke generator with a heated plate. In the samples of Slavoska slanina smoked in a traditional manner, the presence of 11 out of 16 analyzed PAHs was determined (Nap, Anl, Ane, Fln, Ant, Phen, Flt, BaA, Pyr, BbF, BkF). In the samples smoked in industrial conditions, only 2 out of 16 (Nap, Anl) were quantified. In the samples smoked with open fire (the traditional method), PAH4 (BaA, BaP BbF, Chry) concentations were as follows: 14.84 μg kg−1 in the middle, 10.60 μg kg−1 on the surface and 17.37 μg kg−1 in the skin, while the PAH4 content in the samples smoked in industrial conditions were below the level of quantification (&lt;LOQ). The content of carcinogenic BaP was below the limit of quantification in all investigated samples. These findings support the fact that traditional smoking may result in a product safe for consumption, as far as the prescribed legislative recommendations are concerned, but constant monitoring is still needed.

Effects of dielectric barrier discharge cold plasma treatment on the structure and binding capacity of aroma compounds of myofibrillar proteins from dry-cured bacon

The aim of this work was to investigate the influence of dielectric barrier discharge cold plasma (DBD-CP) on the structure and aroma compounds binding capacity of myofibrillar proteins (MPs) extracted from Chinese dry-cured bacon. MPs were treated with DBD-CP at 0, 50, 60 and 70 kV for 150s to monitor the binding ability with aroma compounds such as 3-methyl-butanal, 2-methyl-butanal, nonanal, heptanal and octanal, microstructure, primary and secondary structure changes of MPs using GC-MS, SDS-PAGE, scanning electron microscope (SEM) and FTIR spectroscopy. FTIR spectroscopy revealed a decrease in the α-helices structure while an increasing portion of β-sheets and random coils for all treatments, the relative contents of β-turns had no significant difference between treatments. The flavor compounds binding capacity of MPs enhanced from 50 kV to 70 kV treatment, probably due to the different modifications in protein structure and surface, also the oxidation systems generated by DBD-CP treatment increased hydrophobicity and unfolding of MPs. The result also showed that hydrophobic amino acids increased from 50 kV to 70 kV treatment which could be related to the improvement of binding ability. This study demonstrated that DBD-CP could be exploited to modify the functionality of MPs and improve the flavor of meat products.

Effect of partial substitution of NaCl by KCl on physicochemical properties, biogenic amines and N-nitrosamines during ripening and storage of dry-cured bacon.

Effects of three salting treatments (Formulation II: 80% NaCl+20% KCl; Formulation III: 60% NaCl+40% KCl and Formulation IV: 40% NaCl+60% KCl) on physicochemical properties, residual nitrite, N-nitrosamines and biogenic amines were compared with those of control bacons (Formulation I: 100% NaCl) during processing and storage. Results showed that there were no significant differences among treatments for moisture, pH, and total volatile basic nitrogen (TVBN) content in dry-cured bacons during processing. The replacement of 40% or less NaCl by KCl had no negative effects on the sensory quality of bacons during processing. Formulation III significantly reduced putrescine, cadaverine and histamine contents and enhanced nitrite residues compared with the control. After 12-day ripening and during storage, the substitution of NaCl by 60% KCl significantly increased the N-nitrosodimethylamine (NDMA) content than the control. Principal component analysis showed that there were positive correlations between TVBN, biogenic amines (putrescine, cadaverine, histamine and tyramine) and NDMA, and negative correlation between NDMA and nitrite. These findings suggested the partial substitution of NaCl by KCl could be utilized for producing reduced-sodium dry-cured bacons to improve safety of finished products.

Changes in Protein Hydrolysates During Processing of Chinese Traditional Dry-Cured Bacon (Laròu) Production

Protein and its degradation products are the main nutrients and flavor precursors in pork products. In this study, protein, total nitrogen (TN), water-soluble nitrogen (WSN), peptides, and free amino acids (FAAs) were analyzed during the production process of Chinese traditional dry-cured bacon, “Laròu.” Results indicated that the TN content showed no significant changes throughout the whole process, while the WSN content decreased sharply during the salting period but increased during aging. The sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profile indicated that protein decomposition effectively took place during the late aging period. A decreasing tendency of the total peptides was observed throughout the aging period. On the contrary, the content of total FAAs increased significantly in the final products. Protein degradation and related flavor compound formation mostly occurred during the aging period of the “Laròu” manufacturing. Practical Applications “Laròu” is a popular Chinese dry-cured meat product for its special chewiness and flavor. This study investigates the changes in proteolysis during the process of “Laròu” and provides the theoretical bases for the quality improvement of Chinese traditional dry-cured meat products.

Oxidative stability and antioxidant enzyme activities of dry-cured bacons as affected by the partial substitution of NaCl with KCl

This study investigated the influence of partial substitution of NaCl with KCl on protein and lipid oxidation as well as antioxidant enzyme activities in dry-cured bacons during processing. The partial substitution was 0% KCl (I), 40% KCl (II), and 70% KCl (III). Compared with 0% KCl (I), the substitution of 40% NaCl with KCl did not significantly influence the protein and lipid oxidation and antioxidant enzyme activities. The bacons that were treated with 70% KCl treatment (III) showed increased lipid oxidation and antioxidant enzyme GSH-Px activity, whereas samples treated with formulas I and II showed higher protein oxidation and antioxidant enzyme catalase activity. These results demonstrate that the substitution of NaCl with KCl by more than 40% may significantly affect protein and lipid oxidation and that for the substitution of NaCl in further processed meat products with other chloride salts, salt content is very important for control of protein and lipid biochemical changes in finished products.

The Interaction Between Lipoxygenase-Catalyzed Oxidation and Autoxidation in Dry-Cured Bacon and a Model System.

A model system was conducted to characterize the interaction between lipid autoxidation and enzyme-catalyzed oxidation in dry-cured bacon. This involved the use of a hydroxyl radical (HO•) generating system and the extraction and purification of lipoxygenases (LOX) from pork belly. The results showed that LOX activity rapidly (P < 0.05) increased during the curing of dry-cured bacon. This may be because of the hydroxyl-radical-mediated oxidation from LOX-Fe(2+) to LOX-Fe(3+), which activates LOX. In addition, experiments of the model system also showed that LOX activity could be inhibited by increasing the substrate concentration, although substrate type and concentration had no effect on autoxidation. Moreover, LOX enzyme-catalyzed oxidation and autoxidation could act synergistically to promote lipid oxidation irrespective of the substrate (linoleic or arachidonic acid). These results provide useful information for regulating lipid oxidation during the production of dry-cured pork products.

Industrial Applications of SelectedJFSArticles

Industrial Applications of Selected<i>JFS</i>Articles

Effects of plant polyphenols and α-tocopherol on lipid oxidation, microbiological characteristics, and biogenic amines formation in dry-cured bacons.

Effects of plant polyphenols (tea polyphenol [TP], grape seed extract [GSE], and gingerol) and α-tocopherol on physicochemical parameters, microbiological counts, and biogenic amines were determined in dry-cured bacons at the end of ripening. Results showed that plant polyphenols and α-tocopherol significantly decreased pH, thiobarbituric acid reactive substances content, and total volatile basic nitrogen (TVBN) compared with the control (P < 0.05). Microbial counts and biogenic amine contents in dry-cured bacons were affected by plant polyphenols or α-tocopherol, with TP being the most effective (P < 0.05) in reducing aerobic plate counts, Enterobacteriaceae, Micrococcaceae, yeast, and molds, as well as in inhibiting formation of putrescine, cadaverine, tyramine, and spermine. Principal component analysis indicated that the first 2 principal components (PC) explained about 85.5% of the total variation. PC1 was related with physicochemical factors, parts of biogenic amines, and spoilage microorganisms, whereas PC2 grouped the TVBN, tyramine, 2-phenylethylamine, yeast, and molds. These findings suggest that plant polyphenols, especially TP, could be used to process dry-cured bacons to improve the quality and safety of finished products.

Influence of partial replacement of NaCl with KCl on profiles of volatile compounds in dry-cured bacon during processing

This study investigated the influence of partial substitution of NaCl with KCl on the formation of volatile compounds in bacons during processing using a purge and trap dynamic headspace GC/MS system. Three substitutions were 0% KCl (I), 40% KCl (II), and 70% KCl (III). The profiles of the volatile compounds significantly changed during processing, particularly during the drying/ripening. At the end of process, the bacons from substitution III formed significantly higher levels of lipid-derived volatiles, such as straight chain aldehydes, hydrocarbons than bacons from substitution I and II, whereas the latter formed higher levels of volatiles from amino acid degradation such as 3-methylbutanal. There were very few differences in volatile formation between 0% and 40% KCl application. These results suggest that K+ substitution of Na+ by more than 40% may significantly change profiles of volatiles in finished dry-cured bacons and therefore would result in changes in the product aroma and/or flavour.

Effects of plant polyphenols and α-tocopherol on lipid oxidation, residual nitrites, biogenic amines, and N-nitrosamines formation during ripening and storage of dry-cured bacon

Effects of plant polyphenols (green tea polyphenols (GTP) and grape seed extract (GSE)) and α-tocopherol on physicochemical parameters, lipid oxidation, residual nitrite, microbiological counts, biogenic amines, and N-nitrosamines were determined in bacons during dry-curing and storage. Results show that plant polyphenols and α-tocopherol significantly decreased pH, lipid oxidation (formation of thiobarbituric acid reactive substances) and residual nitrite content compared with control (P < 0.05) at the end of ripening. Microbial counts, biogenic amines, and N-nitrosodimethylamine (NDMA) contents in dry-cured bacons were significantly affected by plant polyphenols or α-tocopherol (P < 0.05), with GTP being the most effective in reducing aerobic plate counts (APC), Enterobacteriaceae, and biogenic amines (putrescine, cadaverine, histamine, tyramine and spermine), as well as in inhibiting the NDMA formation (P < 0.05). Principal component analysis indicated that there were positive correlations between physicochemical factors, biogenic amines (putrescine, cadaverine, histamine, tyramine and spermine), NDMA and APC, and between the TBARS and sodium nitrite. There was a negative correlation between NDMA and nitrite. These findings suggest plant polyphenols, especially GTP, could be utilized for processing dry-cured bacons to improve quality, shelf life, and safety of finished products.

Proteolysis and sensory properties of dry-cured bacon as affected by the partial substitution of sodium chloride with potassium chloride

Quadriceps femoris muscle samples (48) from 24 pigs were processed into dry-cured bacon. This study investigated the influence of partial substitution of sodium chloride (NaCl) with potassium chloride (KCl) on proteolysis and sensory properties of dry-cured bacon. Three salt treatments were considered, namely, I (100% NaCl), II (60% NaCl, 40% KCl), and III (30% NaCl, 70% KCl). No significant differences were observed among treatments in the proteolysis, which was reflected by SDS–PAGE, proteolysis index, amino acid nitrogen, and peptide nitrogen contents. Furthermore, there were no significant differences in the moisture content between control and treatment II, whereas the moisture content in treatment III was significantly higher (p<0.05) in comparison with control (treatment I). The sensory analysis indicated that it was possible to reduce NaCl by 40% without adverse effects on sensory properties, but 70% replacement of NaCl with KCl resulted in bacon with less hardness and saltiness and higher (p<0.05) juiciness and bitterness.

Lipolysis and lipid oxidation in bacon during curing and drying–ripening

Dry-cured bacons were processed using pig bacon belly as material by dry-salting and drying–ripening. Lipolysis and lipid oxidation in intramuscular lipids were studied by evaluating the changes in lipid composition, lipolytic enzymes and lipoxygenase (LOX) activities, peroxide value (POV) and TBARS during processing. Lipid composition showed a significant decrease ( p < 0.05) in phospholipids and an increase ( p < 0.05) in free fatty acids ( r = −0.85, p = 0.0004). All lipolytic activities decreased ( p < 0.05) with increasing process time. Acid lipase showed higher activity than did neutral lipase ( p < 0.05) throughout the processing. LOX activity increased significantly during salting ( p < 0.01) and thereafter decreased. High salt content inhibited acid lipase and phospholipase activities but promoted LOX activity. Both POV and TBARS decreased ( p < 0.05) with temperature rising during the last ripening period, suggesting that rising temperature in this period could lower oxidation indices in products. LOX was closely correlated with TBARS ( r = 0.94) but not with POV ( r = 0.36), indicating that LOX could facilitate lipid secondary oxidation.

Investigations on N-Nitrosopyrrolidine in Dry-Cured Bacon

Dry-cured or "country-style" bacon is a low volume specialty product typically made by small producers whose production practices vary widely. These practices include the direct application of dry-cure formulations containing varying concentrations of salt, sugar, flavoring agents, sodium nitrite, and sometimes sodium nitrate, and the use of lengthy curing and processing times. Because of the possibility of generating higher levels of N-nitrosopyrrolidine (NPYR) after frying in this product type compared with pump-cured bacon, an investigation was carried out on dry-cured bacon obtained from cooperating state or federally inspected establishments. Three different samples from each of the 16 plants were analyzed. Only one sample from each of 2 different producers exceeded the Food Safety and Inspection Service (FSIS) action level of 17 ppb NPYR, indicating that the majority of samples tested were in compliance. A significant correlation (P less than 0.01) was found between residual NaNO2 prior to frying and NPYR after frying. The elimination of added nitrate in the dry-cure formulations is recommended.

Comparison of Three Methods for Determination of /V-Nitrosopyrrolidine in Fried Dry-Cured and Pump-Cured Bacon

Abstract Three methods, the mineral oil distillation (MOD), the dry column (DC), and a low temperature vacuum distillation (LTVD), for the determination of iV-nitrosopyrrolidine in dry-cured and pump-cured bacon were compared. Each method uses the thermal energy analyzer for the determinative step. The coefficients of variation for repeatability were 10.3% (MOD), 7.2% (DC), and 9.1% (LTVD) for the dry-cured bacon study and 8.7% (MOD), 8.5% (DC), and 7.1% (LTVD) for the pump-cured bacon study. The pooled coefficients of variation for between-method reproducibility were 11.8% for the drycured bacon and 10.8% for the pump-cured bacon. The pooled coefficients of variation for repeatability were 9.0% for the dry-cured bacon and 8.2% for the pump-cured bacon. These values compare favorably with the values from previous collaborative or validation studies of the individual methods, and the methods can be considered to be equivalent

Use of Antioxidant-Coated Salts as N-Nitrosamine Inhibitors in Dry- and Brine-Cured Bacon

Several experiments were completed to further evaluate use of α-tocopherol-coated salts as inhibitors of N-nitrosamine formation in fried bacon. Studies with dry-cured bacon prepared with various levels of α-tocopherol indicated that the chemical did not contribute to formation of N-nitrosodimethylamine (NDMA). N-Nitrosopyrrolidine levels for the α-tocopherol-treated bacon samples were generally below 5 μg/kg, which represents an average reduction of approximately 70%. Experiments were also done to evaluate the role of lecithin as a possible precursor of NDMA in brine-cured bacon. At concentrations used to disperse α-tocopherol in the curing brine, lecithin did not contribute to NDMA formation in bacon prepared with α-tocopherol-coated salts.